/**
 * @Author yinyunqi
 * @date 2018年1月23日
 * @Content 验证码
 */
package com.yongqi.pub;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Arrays;
import java.util.Random;

import javax.imageio.ImageIO;

public class ValidateCode {
    
    public static final String VERIFY_CODES = "23456789ABCDEFGHJKLMNPQRSTUVWXYZ";
    private static Random random = new Random();
    /**
     * 使用指定源生成验证码
     * @param verifySize
     * @return
     */
    public static String generateVerifyCode(int verifySize) {
	return generateVerifyCode(verifySize,VERIFY_CODES);
    }
    /**
     * 使用指定源生成验证码
     * @param verifySize 验证码长度
     * @param sources 验证码字符源
     * @return
     */
    public static String generateVerifyCode(int verifySize,String sources) {
	//若没有给出指定源，则使用已定义源
	if (sources == null || sources.length() ==0) {
	    sources = VERIFY_CODES;
	}
	int codesLen = sources.length();
	Random rand = new Random(System.currentTimeMillis());
	//String类型改变时等同生成一个新的String，然后将指针指向新的String对象
	//StringBuffer每次结果都会对StringBuffer进行操作，字符串对象经常改变时使用
	//而在某种情况下String对象的字符串拼接，如String s = "this"+"is"+"string"效率比StringBuffer快，对jvm来说就是String s = "this is string"
	//如果字符串是来自另一个String对象速度就没有优势了
	//StringBuffer是线程安全的可变字符序列，一个类似String的字符串缓冲区，但不能修改
	//可将字符缓冲区安全地用于多个线程，可以在必要时对这些方法进行同步，因此任意特定实例上的所有操作就好像以串行顺序发生的
	//该顺序与所涉及的每个线程进行的方法调用顺序一致
	//StringBuilder提供一个与StringBuffer兼容的API，但不保证同步，被设计用作StringBuffer的简易替换，用在字符缓冲区被单个线程使用的时候
	StringBuilder verifyCode = new StringBuilder(verifySize);
	for(int i=0;i<verifySize;i++) {
	    //verifyCode获取随机获取字符源的字符
	    //Random.nextInt(int n)生成一个随机的int值，值介于[0,n)
	    verifyCode.append(sources.charAt(rand.nextInt(codesLen-1)));
	}
	return  verifyCode.toString();
    }
    /**
     * 生成随机验证码文件，并返回验证码
     * @param w
     * @param h
     * @param outputFile
     * @param verifySize
     * @return
     * @throws IOException
     */
    public static String outputVerifyImage(int w,int h,File outputFile,int verifySize) throws IOException{
	String verifyCode = generateVerifyCode(verifySize);
	outputImage(w,h,outputFile,verifyCode);
	return verifyCode;
    }
    /**
     * 输出随机验证码图片流并返回验证码
     * @param w
     * @param h
     * @param os
     * @param verifySize
     * @return
     * @throws IOException
     */
    public static String outputVerifyImage(int w,int h,OutputStream os,int verifySize) throws IOException{
	String verifyCode = generateVerifyCode(verifySize);
	outputImage(w,h,os,verifyCode);
	return verifyCode;
    }
    /**
     * 生成指定验证码图像文件
     * @param w
     * @param h
     * @param outputFile
     * @param code
     * @throws IOException
     */
    public static void outputImage(int w,int h,File outputFile,String code) throws IOException{
	if (outputFile == null) {
	    return;
	}
	File dir = outputFile.getParentFile();
	if (!dir.exists()) {
	    dir.mkdirs();
	}
	try {
	    outputFile.createNewFile();
	    FileOutputStream fos = new FileOutputStream(outputFile);
	    outputImage(w, h, fos, code);
	    fos.close();
	}catch (IOException e) {
	    throw e;
	}
    }
    /**
     * 输出指定验证码图片流
     * @param w
     * @param h
     * @param os
     * @param code
     * @throws IOException
     */
    public static void outputImage(int w,int h,OutputStream os,String code)throws IOException{
	int verifySize = code.length();
	//TYPE_INT_RGB创建一个不带透明色的BufferedImage对象
	BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
	Random rand = new Random();
	//image对象上获得了绘图对象
	Graphics2D g2 = image.createGraphics();
	g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
	Color[] colors = new Color[5];
	Color[] colorSpaces = new Color[] { Color.WHITE, Color.CYAN,
                Color.GRAY, Color.LIGHT_GRAY, Color.MAGENTA, Color.ORANGE,
                Color.PINK, Color.YELLOW };
        float[] fractions = new float[colors.length];
        for(int i = 0; i < colors.length; i++){
            colors[i] = colorSpaces[rand.nextInt(colorSpaces.length)];
            fractions[i] = rand.nextFloat();
        }
        Arrays.sort(fractions);
        g2.setColor(Color.GRAY);// 设置边框色
        g2.fillRect(0, 0, w, h);
        Color c = getRandColor(200, 250);
        g2.setColor(c);// 设置背景色
        g2.fillRect(0, 2, w, h-4);
        //绘制干扰线
        Random random = new Random();
        g2.setColor(getRandColor(160, 200));// 设置线条的颜色
        for (int i = 0; i < 20; i++) {
            int x = random.nextInt(w - 1);
            int y = random.nextInt(h - 1);
            int xl = random.nextInt(6) + 1;
            int yl = random.nextInt(12) + 1;
            g2.drawLine(x, y, x + xl + 40, y + yl + 20);
        }
        // 添加噪点
        float yawpRate = 0.05f;// 噪声率
        int area = (int) (yawpRate * w * h);
        for (int i = 0; i < area; i++) {
            int x = random.nextInt(w);
            int y = random.nextInt(h);
            int rgb = getRandomIntColor();
            image.setRGB(x, y, rgb);
        }
        shear(g2, w, h, c);// 使图片扭曲
        g2.setColor(getRandColor(100, 160));
        int fontSize = h-4;
        Font font = new Font("Algerian", Font.ITALIC, fontSize);
        g2.setFont(font);
        char[] chars = code.toCharArray();
        for(int i = 0; i < verifySize; i++){
            AffineTransform affine = new AffineTransform();
            affine.setToRotation(Math.PI / 4 * rand.nextDouble() * (rand.nextBoolean() ? 1 : -1), (w / verifySize) * i + fontSize/2, h/2);
            g2.setTransform(affine);
            g2.drawChars(chars, i, 1, ((w-10) / verifySize) * i + 5, h/2 + fontSize/2 - 10);
        }
        g2.dispose();
        //输出
        ImageIO.write(image, "jpg", os);
    }
    private static Color getRandColor(int fc, int bc) {
        if (fc > 255)
            fc = 255;
        if (bc > 255)
            bc = 255;
        int r = fc + random.nextInt(bc - fc);
        int g = fc + random.nextInt(bc - fc);
        int b = fc + random.nextInt(bc - fc);
        return new Color(r, g, b);
    }
     
    private static int getRandomIntColor() {
        int[] rgb = getRandomRgb();
        int color = 0;
        for (int c : rgb) {
            color = color << 8;
            color = color | c;
        }
        return color;
    }
     
    private static int[] getRandomRgb() {
        int[] rgb = new int[3];
        for (int i = 0; i < 3; i++) {
            rgb[i] = random.nextInt(255);
        }
        return rgb;
    }
 
    private static void shear(Graphics g, int w1, int h1, Color color) {
        shearX(g, w1, h1, color);
        shearY(g, w1, h1, color);
    }
     
    private static void shearX(Graphics g, int w1, int h1, Color color) {
 
        int period = random.nextInt(2);
 
        boolean borderGap = true;
        int frames = 1;
        int phase = random.nextInt(2);
 
        for (int i = 0; i < h1; i++) {
            double d = (double) (period >> 1)
                    * Math.sin((double) i / (double) period
                            + (6.2831853071795862D * (double) phase)
                            / (double) frames);
            g.copyArea(0, i, w1, 1, (int) d, 0);
            if (borderGap) {
                g.setColor(color);
                g.drawLine((int) d, i, 0, i);
                g.drawLine((int) d + w1, i, w1, i);
            }
        }
 
    }
 
    private static void shearY(Graphics g, int w1, int h1, Color color) {
 
        int period = random.nextInt(40) + 10; // 50;
 
        boolean borderGap = true;
        int frames = 20;
        int phase = 7;
        for (int i = 0; i < w1; i++) {
            double d = (double) (period >> 1)
                    * Math.sin((double) i / (double) period
                            + (6.2831853071795862D * (double) phase)
                            / (double) frames);
            g.copyArea(i, 0, 1, h1, 0, (int) d);
            if (borderGap) {
                g.setColor(color);
                g.drawLine(i, (int) d, i, 0);
                g.drawLine(i, (int) d + h1, i, h1);
            }
 
        }
 
    }
//    public static void main(String[] args) throws IOException{
//        File dir = new File("F:/verifies");
//        int w = 200, h = 80;
//        for(int i = 0; i < 50; i++){
//            String verifyCode = generateVerifyCode(4);
//            File file = new File(dir, verifyCode + ".jpg");
//            outputImage(w, h, file, verifyCode);
//        }
//    }
}

